Heat sensitivity and protein synthesis during heat-shock in the tobacco hornworm, Manduca sexta.
Fifth instar larvae of the tobacco hornworm, Manduca sexta, tolerate 1-h exposures to temperatures as high as 42 degrees C. Above 42 degrees C, survival declines rapidly to 18% at 44 degrees C and 0% at 48 degrees C. As in other insects, the heat-shock response of Manduca sexta involves the induction of synthesis of heat-shock proteins very similar in size to the Drosophila heat-shock proteins (84, 73, 71, 27, 25, 23, and 22 kd). In the epidermis, heat-shock protein synthesis peaks at 42 degrees C, correlating with the heat sensitivity of both the tissue itself and the intact larva. Some heat-shock proteins have different isoelectric forms depending on tissue. Also, the heat-shock proteins are synthesized over a wider range of temperatures in the imaginal discs and the fat body as compared to the epidermis. In contrast to dipteran insects, Manduca sexta does not exhibit a strong repression of non-heat-shock protein synthesis under tolerable conditions.
Fittinghoff
C M
CM
Department of Zoology, University of Washington, Seattle 98195.
Riddiford
L M
LM
D000818:Animals; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006358:Hot Temperature / Q000009:adverse effects*; D007313:Insecta / Q000378:metabolism; D007700:Kinetics; D007814:Larva / Q000378:metabolism; D007915:Lepidoptera / Q000378:metabolism*; D008297:Male; D012867:Skin / Q000378:metabolism; D013045:Species Specificity; D013312:Stress, Physiological / Q000378:metabolism
D006360:Heat-Shock Proteins